Interpretive Summary: Callipyge lambs have increased feed efficiency and yield of lean meat. However, callipyge lambs produce inherently tough meat, especially the loin muscle, when compared to normal lambs. Attempts have been made to identify a commercially feasible method to improve the tenderness of callipyge meat to an acceptable level to consumers with little success. The goal of this study was to evaluate the effect of a pH-enhancing technology on tenderness of several muscles from callipyge lambs. The increased pH treatment improved consumer impression of portion size, color, and overall appearance. In addition, consumer evaluation of eating quality, including tenderness, was improved such that pH-treated meat from callipyge lamb was similar to untreated meat from normal lamb for many traits and only slightly less tender. Overall, pH-enhancement improved both appearance and palatability of meat from callipyge lamb, thereby improving consumer acceptability to near the levels of meat from normal lamb. Thus, this technology may make it commercially feasible to routinely produce callipyge lamb.

Technical Abstract:
This research was to determine if BPI Processing Technology improved palatability of normal (NN) and callipyge (CN) lamb meat and determine the mechanism by which palatability was improved. Ten ewe and 10 wether lambs of each phenotype were harvested and carcass traits were assessed by a trained evaluator. The longissimus (LM) muscle was removed at 2 d postmortem. Alternating sides served as either control (CON) or treated with BPI Processing Technology (BPT). Muscles designated BPT were injected to a target 120% by weight with a patented solution containing water, ammonium hydroxide, carbon monoxide, and salt. Muscle pH, cooking loss, Warner-Bratzler shear force (WBS), sarcomere length, cooked moisture retention, and desmin degradation were measured. A trained sensory panel and a take-home consumer panel evaluated LM chops. Callipyge had a heavier live and hot carcass weights, less adjusted fat thickness, lower yield grades, and higher conformation scores than NN (P < 0.05). For LM, NN had shorter sarcomeres, lower WBS values, higher juiciness ratings, more off-flavors, lower consumer ratings for raw characteristics (like of portion size, like of color, like of leanness, overall like of appearance) and higher consumer ratings for eating characteristics (like of juiciness, like of flavor) than CN (P < 0.05). For LM, BPT had higher cooked moisture retention, lower WBS values, higher juiciness ratings, less off-flavors, and higher consumer ratings for raw characteristics (like of portion size, like of color, overall like of appearance), and eating characteristics (like of juiciness, like of flavor) than CON (P < 0.05). Significant phenotype by treatment interactions occurred for LM muscle pH, desmin degradation, tenderness, consumer like of texture/tenderness, and consumer overall like of eating quality (P < 0.05). For LM, BPT increased muscle pH more for NN than CN (P < 0.01) and increased desmin degradation for NN, but decreased desmin degradation for CN (P < 0.01). The BPT-enhancement improved LM tenderness ratings for CN more than NN (P < 0.05). For consumer like of texture/tenderness, BPT improved ratings for CN more than NN (P < 0.01). For consumer overall like of eating quality, BPT improved ratings for CN more than NN (P < 0.05). In summary, BPI Processing Technology had little to no effect on sarcomere length and desmin degradation, but improved palatability of normal and callipyge lamb, by increasing cooked moisture retention, improving consumer acceptability of callipyge to near-normal levels.